go in kernel config and unset that option which disables crypto tests
and notice that on boot it can't boot because some crypto fails
but this crypto is not used for me

but because testing it fails... it makes me unable to boot/mount the crypt device

the line is printed from:
linux315/src/linux-3.15/crypto/testmgr.c
pr_err("alg: skcipher%s: %s failed on test %d for %s: ret=%d\n",
                                       d, e, j, algo, -ret);

but this is not where the error is....

actually disabling CONFIG_CRYPTO_DEV_CCP , passes all tests i guess, with this:
[    0.489067] alg: No test for stdrng (krng)

that is: Support for AMD Cryptographic Coprocessor 

but previously has all these on:
[*]   Support for AMD Cryptographic Coprocessor
<*>     Cryptographic Coprocessor device driver
<*>       Encryption and hashing acceleration support

